Thiram is the simplest thiuram disulfide and the oxidized dimer of dimethyldithiocarbamate. It is used as a fungicide, ectoparasiticide to prevent fungal diseases in seed and crops and similarly as an animal repellent to protect fruit trees and ornamentals from damage by rabbits, rodents and deer. It is effective against Stem gall of coriander, damping off, smut of millet, neck rot of onion, etc. Thiram has been used in the treatment of human scabies, as a sun screen and as a bactericide applied directly to the skin or incorporated into soap.[4]

Thiram
Structural formula of thiram
Ball-and-stick model of the thiram molecule
Names
Preferred IUPAC name
Dimethylcarbamothioic dithioperoxyanhydride
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.004.806 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C6H12N2S4/c1-7(2)5(9)11-12-6(10)8(3)4/h1-4H3 ☒N
    Key: KUAZQDVKQLNFPE-UHFFFAOYSA-N ☒N
  • InChI=1/C6H12N2S4/c1-7(2)5(9)11-12-6(10)8(3)4/h1-4H3
    Key: KUAZQDVKQLNFPE-UHFFFAOYAK
  • CN(C)C(=S)SSC(=S)N(C)C
Properties
C6H12N2S4
Molar mass 240.42 g·mol−1
Appearance White to yellow crystalline powder
Odor Characteristic[vague][1]
Density 1.29 g/cm3[1]
Melting point 155 to 156 °C (311 to 313 °F; 428 to 429 K)
Boiling point decomposes[1]
30 mg/L
Vapor pressure 0.000008 mmHg (20 °C)[1]
Pharmacology
P03AA05 (WHO)
Hazards
Flash point 138 °C (280 °F)[2]
Lethal dose or concentration (LD, LC):
1350 mg/kg (mouse, oral)
210 mg/kg (rabbit, oral)
560 mg/kg (rat, oral)[3]
500 mg/m3 (rat, 4 hr)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 5 mg/m3[1]
REL (Recommended)
TWA 5 mg/m3[1]
IDLH (Immediate danger)
100 mg/m3[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Thiram is also used as a sulfur source and secondary accelerator the sulfur vulcanization of rubbers.

Usage

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Map of agricultural use in the U.S. (2012)

Thiram was traditionally used in apple and wine farming. Since 2010 most thiram is applied to soybeans.

Chemical properties

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Thiram is a type of sulfur fungicide. It has been found to dissolve completely in chloroform, acetone, and ether. It is available as dust, flowable, wettable powder, water-dispersible granules, and water suspension formulations and in mixtures with other fungicides.[4]

Thiram is nearly immobile in clay soils or in soils of high organic matter. It is not expected to contaminate groundwater because of its in-soil half life of 15 days, in addition to its tendency to adhere to soil particles.[5]

As a waste, thiram carries an EPA U244 code.

Toxicity

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Thiram is moderately toxic by ingestion, but it is highly toxic if inhaled. Acute exposure in humans may cause headaches, dizziness, fatigue, nausea, diarrhea, and other gastrointestinal complaints.[6]

Chronic or repeated exposure may cause sensitive skin, and it may have effects on the thyroid or liver.[7]

References

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  1. ^ a b c d e f g NIOSH Pocket Guide to Chemical Hazards. "#0612". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ U.S. Department of Agriculture, Soil Conservation Service. 1990 (Nov). SCS/ARS/CES Pesticide Properties Database: Version 2.0 (Summary). USDA - Soil Conservation Service, Syracuse, NY.
  3. ^ a b "Thiram". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ^ a b "Thiram". Extension Toxicology Network.
  5. ^ Howard, P.H., ed. (1989). Handbook of Environmental Fate and Exposure Data for Organic Chemicals. Vol. III: Pesticides. Chelsea, MI: Lewis Publishers.
  6. ^ Hayes, W.J. and E.R. Laws, ed. (1990). Handbook of Pesticide Toxicology. Vol. 3, Classes of Pesticides. NY: Academic Press, Inc.
  7. ^ NIOSH - Thiram International Chemical Safety Card (ICSC July 22, 2015
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  • Thiram in the Pesticide Properties DataBase (PPDB)